<template>
  <div class="app-container">
    课程列表
    <!-- 表格 -->
    <!--查询表单-->
    <el-form :inline="true" class="demo-form-inline">
      <!-- 所属分类：级联下拉列表 -->
      <!-- 一级分类 -->
      <el-form-item label="课程类别">
        <el-select
          v-model="courseQueryVO.subjectParentId"
          placeholder="请选择"
          @change="subjectLevelOneChanged"
        >
          <el-option
            v-for="subject in subjectOneList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>

        <!-- 二级分类 -->
        <el-select v-model="courseQueryVO.subjectId" placeholder="请选择">
          <el-option
            v-for="subject in subjectTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>
      </el-form-item>

      <!-- 标题 -->
      <el-form-item>
        <el-input v-model="courseQueryVO.title" placeholder="课程标题" />
      </el-form-item>
      <!-- 讲师 -->
      <el-form-item>
        <el-select v-model="courseQueryVO.teacherId" placeholder="请选择讲师">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"
          />
        </el-select>
      </el-form-item>

      <el-button type="primary" icon="el-icon-search" @click="getList()"
        >查询</el-button
      >
      <el-button type="default" @click="resetData()">清空</el-button>
    </el-form>
    <!-- 表格 -->
    <el-table
      v-loading="listLoading"
      :data="list"
      element-loading-text="数据加载中"
      border
      fit
      highlight-current-row
      row-class-name="myClassList"
    >
      <el-table-column label="序号" width="70" align="center">
        <template slot-scope="scope">
          {{ (page - 1) * limit + scope.$index + 1 }}
        </template>
      </el-table-column>

      <el-table-column label="课程信息" width="470" align="center">
        <template slot-scope="scope">
          <div class="info">
            <div class="pic">
              <img :src="scope.row.cover" alt="scope.row.title" width="150px" />
            </div>
            <div class="title">
              <a href="">{{ scope.row.title }}</a>
              <p>{{ scope.row.lessonNum }}课时</p>
            </div>
          </div>
        </template>
      </el-table-column>

      <el-table-column label="创建时间" align="center">
        <template slot-scope="scope">
          {{ scope.row.gmtCreate.substr(0, 10) }}
        </template>
      </el-table-column>
      <el-table-column label="发布时间" align="center">
        <template slot-scope="scope">
          {{ scope.row.gmtModified.substr(0, 10) }}
        </template>
      </el-table-column>
      <el-table-column label="价格" width="100" align="center">
        <template slot-scope="scope">
          {{
            Number(scope.row.price) === 0
              ? "免费"
              : "¥" + scope.row.price.toFixed(2)
          }}
        </template>
      </el-table-column>
      <el-table-column
        prop="buyCount"
        label="付费学员"
        width="100"
        align="center"
      >
        <template slot-scope="scope"> {{ scope.row.buyCount }}人 </template>
      </el-table-column>

      <el-table-column label="操作" width="150" align="center">
        <template slot-scope="scope">
          <router-link :to="'/course/info/' + scope.row.id">
            <el-button type="text" size="mini" icon="el-icon-edit"
              >编辑课程信息</el-button
            >
          </router-link>
          <router-link :to="'/course/chapter/' + scope.row.id">
            <el-button type="text" size="mini" icon="el-icon-edit"
              >编辑课程大纲</el-button
            >
          </router-link>
          <el-button
            type="text"
            size="mini"
            icon="el-icon-delete"
            @click="removeCourseById(scope.row.id)"
            >删除</el-button
          >
        </template>
      </el-table-column>
    </el-table>

    <!-- 分页 -->
    <el-pagination
      :current-page="page"
      :page-size="limit"
      :total="total"
      style="padding: 30px 0; text-align: center"
      layout="total, prev, pager, next, jumper"
      @current-change="getList"
    />
  </div>
</template>
<script>
import course from "@/api/edu/course";
import subject from "@/api/edu/subject";
export default {
  // 核心代码
  // 定义变量和初始值
  data() {
    return {
      listLoading: true, // 是否显示loading信息
      // 查询之后接口返回集合
      list: null,
      page: 1,
      limit: 5,
      total: 0,
      // 条件封装对象
      courseQueryVO: {
        subjectParentId: "",
        subjectId: "",
        title: "",
        teacherId: "",
      },
      teacherList: [], // 讲师列表
      subjectOneList: [], // 一级分类列表
      subjectTwoList: [], // 二级分类列表,
    };
  },
  // 页面渲染之前执行 一般调用methods里面的方法
  created() {
    // 当前页面加载时获取数据
    this.getList();
    // 初始化分类列表
    this.initSubjectList();
    // 获取讲师列表
    this.initTeacherList();
  },
  methods: {
    // 获取分类列表
    initSubjectList() {
      subject.getSubjectList().then((response) => {
        this.subjectOneList = response.data;
      });
    },
    // 获取讲师列表
    initTeacherList() {
      course.getListTeacher().then((response) => {
        this.teacherList = response.data;
      });
    },
    // 创建具体的方法  调用course.js 里面具体的方法
    getList(page = 1) {
      this.page = page;
      this.listLoading = true;
      course
        .getCourseListPage(this.page, this.limit, this.courseQueryVO)
        // 请求成功执行
        .then((response) => {
          // console.log(response.data);
          // 把请求到的数据 赋值给list空集合
          this.total = response.data.total;
          this.list = response.data.records;
          this.listLoading = false;
        })
        // 请求失败执行
        .catch((error) => {
          console.log(error);
        });
    },
    // 点击某个一级分类 触发change  显示二级分类
    subjectLevelOneChanged(value) {
      // 这里的value是一级分类的id值
      // 遍历所有的分类 包括一级分类和二级分类
      for (let index = 0; index < this.subjectOneList.length; index++) {
        // 得到每个一级分类
        const oneSubject = this.subjectOneList[index];
        // 进行判断  每个一级分类的id值 和选择的id值是否相等
        if (value === oneSubject.id) {
          this.subjectTwoList = oneSubject.children;
          // 清空二级分类的id值
          this.courseQueryVO.subjectId = "";
        }
      }
    },
    resetData() {
      // 表单输入项数据清空
      this.courseQueryVO = {};
      // 清空二级分类列表
      this.subjectTwoList = {};
      // 查询所有讲师数据
      this.getList();
    },
    // 根据courseId删除课程
    removeCourseById(id) {
      this.$confirm("此操作将永久删除课程, 是否继续?", "提示", {
        confirmButtonText: "确定",
        cancelButtonText: "取消",
        type: "warning",
      }).then(() => {
        // 调用删除的方法
        course.deleteCourseById(id).then((response) => {
          // 提示信息
          this.$message({
            type: "success",
            message: "删除成功!",
          });
          // 回到列表页面  为了用户体验  这里把当前页传进去 就可以处理不是刷新到当前页的问题
          this.getList(this.page);
        });
      });
    },
  },
};
</script>
<style scoped>
.myClassList .info {
  width: 450px;
  overflow: hidden;
}
.myClassList .info .pic {
  width: 150px;
  height: 90px;
  overflow: hidden;
  float: left;
}
.myClassList .info .pic a {
  display: block;
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
}
.myClassList .info .pic img {
  display: block;
  width: 100%;
}
.myClassList td .info .title {
  width: 280px;
  float: right;
  height: 90px;
}
.myClassList td .info .title a {
  display: block;
  height: 48px;
  line-height: 24px;
  overflow: hidden;
  color: #00baf2;
  margin-bottom: 12px;
}
.myClassList td .info .title p {
  line-height: 20px;
  margin-top: 5px;
  color: #818181;
}
</style>